This is topic popping sound from exhaust in forum Tech Talk at Northern California Ford Owners  .


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Posted by slow5oh (Member # 12881) on :
 
so when I slow down from high rpm's there is a lot of popping coming from my exhaust, should this be something I should worry about? also happens when I downshift.

[ 2013-07-15, 11:47 AM: Message edited by: slow5oh ]
 
Posted by NEIGHT (Member # 8741) on :
 
Are you talking about slowing down as in engine brake(no gas or clutch still in gear). If so yes it's normal for aftermarket exhaust to pop without cats.
 
Posted by norcalfiddy (Member # 11207) on :
 
timing, running rich

nothing to worry about
 
Posted by red5o (Member # 12651) on :
 
quote:
Originally posted by NEIGHT:
Are you talking about slowing down as in engine brake(no gas or clutch still in gear). If so yes it's normal for aftermarket exhaust to pop without cats.
Yea I like that sound [burnout]
 
Posted by slow5oh (Member # 12881) on :
 
quote:
Originally posted by red5o:
quote:
Originally posted by NEIGHT:
Are you talking about slowing down as in engine brake(no gas or clutch still in gear). If so yes it's normal for aftermarket exhaust to pop without cats.
Yea I like that sound [burnout]
lol I have all my cats on though
 
Posted by S351-R (Member # 1605) on :
 
If it backfires excessively and you still have a functional air pump, you may have an air pump diverter valve not functioning properly.

[ 2013-07-16, 12:22 PM: Message edited by: S351-R ]
 
Posted by slow5oh (Member # 12881) on :
 
quote:
Originally posted by S351-R:
If it backfires excessively and you still have a functional air pump, you may have an air pump diverter valve not functioning properly.
it's bot backfiring though, when I engine brake it just sounds like a lot of little pops like I have popcorn in my trunk
 
Posted by coupe5oh (Member # 10411) on :
 
its actually a sign of weak valve springs. on decel the vacuum from the pistons going down is pulling the valves open. it did it on my old 94 but when I rebuilt the engine with new valve springs it never did it again. I didn't know why until my old auto shop teacher explained it to me
 
Posted by slow5oh (Member # 12881) on :
 
quote:
Originally posted by coupe5oh:
its actually a sign of weak valve springs. on decel the vacuum from the pistons going down is pulling the valves open. it did it on my old 94 but when I rebuilt the engine with new valve springs it never did it again. I didn't know why until my old auto shop teacher explained it to me
this won't affect anything when I smog right?
 
Posted by coupe5oh (Member # 10411) on :
 
quote:
Originally posted by slow5oh:
quote:
Originally posted by coupe5oh:
its actually a sign of weak valve springs. on decel the vacuum from the pistons going down is pulling the valves open. it did it on my old 94 but when I rebuilt the engine with new valve springs it never did it again. I didn't know why until my old auto shop teacher explained it to me
this won't affect anything when I smog right?
it shouldn't being that smog is tested under power not decal..my 95 gt does it and I passed smog no problem with a smog legal C.A.I and stock exhaust
 
Posted by slow5oh (Member # 12881) on :
 
okay sounds good, thanks guys
 
Posted by coupe5oh (Member # 10411) on :
 
no problem
 




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